Daddario EXL110-3D

I use these strings for the last 30 years and never had any issues. As of late, I came across several packs with dark spots on strings from freshly opened packs. Unfortunately, on the package, there is no way of checking the date of manufacture. I investigated online and apparently there is a way of contacting Daddario in order to find out how old the strings are. I contacted them and will revert how they are able to help me.